firstly. the linkage of the movements of the bitcoin and ethereum market are clear that ethereums market is shadowing bitcoin. because bitcoin has known market cycles and if ethereum was independent it would not be following bitcoins market cycles. so when it does follow bitcoins market cycles, its obvious that its ethereum that is the follower
That's a great point.
ETH would not profit from attacking bitcoin because:
1. It would have to allocate tremendous resources into that and it would not destroy the network. All it would do is prove that with enough effort it can be done, but we all know it can be done and we all know it such attack cannot be sustained. It's like a DDOS on the whole country. You could do it and cut a country from the Internet for a while, but how much it would cost you and how long would you be able to sustain it?
2. A panic on the bitcoin market would most likely cause a panic on all other coins. If this attack was only to buy more of everything, that might work, but it would not make people flock from one coin to the other. The whole crypto industry is a big ecosystem.
3. What do you thing would happen if bitcoiners found out Vitalik and team are behind the attack? He'd climb above SBF and CSW to become the most hated person in the industry.
To your first point, the problem is that if Bitcoin somehow recovers after an attack, the steal
itself would then be valuable for the attackers. In fact, they could in theory steal so much bitcoin as to pay for the whole thing. And even if they only manage to steal slightly less, they now have the CapEx for future attacks. So they could just keep coming back for seconds!
If attackers gain a 51% majority of the PoW network, and their intent is to crash the value of Bitcoin, they will be able to do so.
To your second point, yes, the whole idea is dependent on the Ethereum stakeholders being able to convince the public that Ethereum isn't connected to Bitcoin. This is definitely worth discussing further (as we are currently doing on this thread). I personally think that with that much money on the line, they will surely be able to do so. (There's also an ongoing discussion about to what extent they are even competitors at all, which is also a relevant discussion.)
And to your last point, Vitalik and co. first of all don't have to take part. It only requires a subset of the Ethereum stakeholders to take part in principle. (And in my preprint, I even describe how they can potentially be completely anonymous.) Second of all, sure the attackers will be hated by the Bitcoin investors that are left behind, and the fans of the blockchain, but who knows, they might be revered by the early migrators from Bitcoin to Ethereum, who will also see their assets increase by perhaps as much as 100%-200%. And not least, they might be liked by a
large part of the public if they can successfully campaign that PoW is a wasteful (and flawed) technology, and that the crash of Bitcoin would thus be good for the planet.